UC-NRLF 


B    3    111    3bS 


SANITATION 
OF  CITIES  . 


WILLIAM  -L*D1OLIER 

AND  STAFF 
OF 

THE  SANITATION  CORPORATION 
NEW  YORK  CITY 


Engineering 
Library 

G-5 

Copyright,  1921, 

by 

THE  SANITATION  CORPORATION 
NEW  YORK 


' 


WILLIAM  L.  D'OLIER 


CONTENTS 

CHAPTER  PAGE 

I     GENERAL  CONSIDERATIONS 3 

II  THE  CITY  PLAN  AND  THE  SANITARY  UTILITIES      .     .  15 

III  WATER  SUPPLY  AND  REMOVAL  OF  SEWAGE      ...  23 

IV  THE  PURIFICATION  OF  WATER  SUPPLIES     ....  43 
V    THE  SEWERAGE  SYSTEM 57 

VI     THE  SEWAGE  TREATMENT  PROBLEM 63 

VII  THE  BIOLOGICAL  TREATMENT  OF  SEWAGE    ....  73 

VIII  DIFFICULT  PROBLEMS  FOUND  IN  TREATING  SEWAGE    .  83 

IX  THE  MECHANICAL  TREATMENT  OF  SEWAGE     ...  89 

X     THE  PURIFICATION  OF  SEWAGE 97 

XI  DEVELOPMENT  OF  COMMERCIAL  WATERWAYS  AS  A 

SANITARY  MEASURE 105 

XII     HIGH  PRESSURE  FIRE  SERVICE in 

XIII     CONCLUDING  REMARKS 117 


7881S2 


WHICH-WILL-NE-BUY? 


J  LLl  NO  IS  STATE  BOMIO  of  H  EALTH  -  CARTQONN°-4 


ONTHE-5ANITY-OF-HJS-CHOICE-THE 
HE^LTH-OF-HIS-CITY-WIUL-DEPEND. 


THE  SANITATION  OF  CITIES 


CHAPTER  I 
GENERAL  CONSIDERATIONS 

BENJAMIN  FRANKLIN  in  one  of  his  wise  sayings 
reminds  us  that  the  choice  of  a  good  whole- 
some situation  to  fix  a  dwelling  in  is  a  very  serious 
affair,  especially  as  not  only  the  comfort  of  living 
but  even  the  necessaries  of  life  depend  in  great 
measure  upon  it;  since  a  family  frequently  sick 
can  rarely,  if  ever,  thrive. 

The  truth  of  this  and  the  wisdom  of  his  advice 
are  obvious.  Sanitation  is  a  broad  subject,  and  in 
the  present  age  is  especially  the  problem  of  the 
city. 

Civilization  is  the  child  of  the  city,  and  the 
true  measure  of  social  advancement  is  made 
manifest  particularly  in  the  comfort,  health  and 
prosperity  of  the  inhabitants  of  cities.  The  an- 
cient municipality  encircled  by  its  strong  walls 
reveals  civil  and  social  conditions  controlled  by 
power  and  served  by  slavery.  Many  cities  are 
written  large  on  the  pages  of  history  which  are 
illumed  thus  with  deathless  glory.  Babylon, 
Nineveh,  Memphis,  Jerusalem,  Troy,  Athens, 


(Seneral  Conefoeratione 

and  Rome  are  names  each  of  which  is  invested 
with  an  infinite  charm,  both  of  grandeur  and 
pathos.  But  we  of  this  utilitarian  age  are  usually 
forced  to  turn  from  their  story,  notwithstanding 
its  enchantment,  with  the  feeling  that  it  offers 
little  to  guide  us,  beyond  affording  lessons  of  what 
to  avoid. 

History  and  archaeology  reveal  abundant  data 
concerning  cities,  their  growth  and  problems, 
and  present  the  drama  of  their  civil  and  political 
experience,  but  teach  very  little  that  is  helpful 
about  their  sanitation  which,  since  it  is  related 
directly  to  human  life,  must  have  been  always  of 
primary  importance.  We  are  told  of  wars,  of 
victories  and  disasters;  of  arts  triumphant  over 
social  degradation;  and  of  slavery.  Ancient 
literature,  immortal,  or  as  nearly  so  as  anything 
human  can  be,  reveals  the  men  of  bygone  ages 
who  seem  still  to  live  and  speak.  But  of  sanita- 
tion there  is  little  to  be  learned  from  ancient 
history  and  literature,  save  only  the  lesson  taught 
by  its  absence.  The  strength  of  cities  and  of 
nations  was  sapped  and  undermined,  often  when 
facing  relentless  enemies  without  the  walls,  by 
the  diseases  within  resulting  from  ignorance  and 
incapacity  to  provide  for  sanitary  needs. 

In  these  ancient  cities  war  carried  off  its  thou- 
sands, and  pestilence  its  tens  of  thousands.  The 
manifold  diseases  described  under  the  names  of 
plague,  black  death,  cholera,  typhoid,  typhus, 


Sanitation  of  Cities 

etc.,  were  due  to  insanitary  conditions;  unclean- 
liness  was  the  predisposing  and  most  powerful 
cause — meaning  by  this  the  accumulations  of 


ANCIENT  EUROPEAN  CITY 

Showing  the  method  of  sewage  disposal  obtaining  in  this  city  at  that  time. 
Waste  matter  pouring  from  the  buildings  into  a  canal 


decaying  animal  and  vegetable  matters  around 
human  habitations,  and  the  saturation  of  the  soil 
with  filth.  Nor  were  the  cities  of  antiquity  the 
only  sufferers  from  these  visitations.  Athens  had 
reached  her  meridian  and  her  sun  had  set;  Rome 
had  passed  into  ruin,  and  yet  the  progress  of 
pestilence  advanced  even  into  our  own  age. 
The  millions  of  deaths  that  history  ascribes 

6 


(Beneral  Consiberations 

to  diseases  and  epidemics,  due  principally  if  not 
altogether  to  the  lack  of  sanitation,  far  exceed 
all  the  losses  of  life  through  the  ages  caused  by 
wars.  It  has  taken  centuries  for  our  race  to  learn 
that  our  greatest  enemy  bears  no  sword  or  stave, 
but  enters  our  camp  unobserved,  like  a  spy — a  re- 
lentless foe,  hidden  within  and  fostered  by  the 
neglected  rubbish  and  offal — that  comes  forth 
from  his  lurking  place  without  warning,  to  strike 
the  human  body  itself,  which  cannot  be  defended 
effectively  against  the  onslaught  of  epidemic  5 
pestilence  when  thus  attacked.  <  u 

The  sanitary  modern  city  has  been  well  de- 
scribed by  an  ingenious  writer  as  the  result  of  a      £  z 
number  of  contributing  developments  which  have 

f    1  I*M  ^ 

created  a  unit  that  may  reasonably  be  compared  >  j 

with  the  human  organism;  with  its  skeleton,  the      ° 

v^     yu 

city  streets;  the  water  distributing  pipes  and 
sewers,  its  arteries  and  veins.  Through  the 
arteries,  sp  called,  courses  the  water  which  is  the  2 

life-blood  of  the  community;  and  through  the  so-       §  fc 
called  veins,  the  sewers,  pass  off  the  liquid  mat-  Jj 

ters  contaminated  in  the  processes  of  the  bodily 
functions.  To  carry  the  simile  further,  the  heart 
might  be  compared  to  the  waterworks  pumping 
plant,  and  the  kidneys  to  the  sewage  disposal 
system. 

Thus  the  city  may  be  looked  upon  as  an 
organism,  as  well  as  a  social  unit,  having  its 
organic  life  and  requiring  for  its  normal  existence 


ftbe  Sanitation  of  Cities 

the  healthful  performance  of  its  various  func- 
tions. 

The  present  century  is  especially  the  age  of 


CROSSNESS,  LONDON,  ENGLAND 

Sewage  pumping  station 

cities.  The  urban  population  of  the  United 
States  in  the  thirty  years  from  1880  to  1910  in- 
creased from  29.5  to  46.3  per  cent,  and  in  the 
last  decade  alone  there  has  been  an  increase  of 
more  than  35  per  cent.  People  prefer  to  live  in 
cities  primarily  because  of  better  facilities  for 
earning  a  living  from  trade  and  industry,  and 
because  of  better  opportunities  for  social  enjoy- 
ment and  recreation.  Secondarily,  because  the 
conveniences  of  life  are  afforded  in  greater 
measure  than  in  rural  communities. 

The  industries  and  commerce  that  are  the 
physical  support  and  wealth  of  a  city  are  largely 
dependent  upon  means  of  communication  and 
transportation  by  rail  and  by  water,  and  upon 

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9 


Sanitation  of  Cities 

the  existence  of  extensive  tributary  areas  from 
which  raw  materials  are  obtainable,  as  well  as 
abundant  supplies  of  food;  and  further,  upon 
sanitation  and  a  naturally  healthful  location. 

Before  the  introduction  of  railways  the  great 
cities  of  the  world  depended  in  almost  every  case 
on  water  transportation  for  their  prosperity;  nor 
has  the  railway  greatly  altered  this.  Access  to 
the  ocean-borne  commerce  of  the  world  and  to 
river  transportation  is  the  greatest  possession 
of  a  city.  With  the  growth  of  cities  there  has 
come  a  great  increase  in  the  mutual  interdepend- 
ence of  their  inhabitants  and  a  more  general 
recognition  of  the  value  of  organized  activity  in 
municipal  life.  In  modern  times  an  essential  por- 


MIAMI,  FLORIDA 
View  of  a  southern  park 

tion  of  the  city's  care  is  preservation  of  law  and 
order,  safety  from  fire,  provision  for  public  works 
and  their  upkeep — such  as  water  supply,  pave- 

10 


(general  Conefoeratione 

ments,  sewerage,  sewage  disposal,  wastes  disposal, 
parks,  public  baths,  and  various  other  social 
conveniences. 

But  it  is  only  in  recent  years  that  serious  efforts 
have  been  made  toward  correlating  these  activi- 
ties, thereby  obtaining  not  only  a  more  economi- 
cal plan  in  the  outlay  of  public  funds,  but  also 
a  much  higher  efficiency.  It  is  self-evident 
that  street  layouts  should  be  related  not  only  to 
the  needs  of  traffic  and  the  marketing  of  real 
property,  but  also  with  regard  to  the  most 
efficient  and  economical  design  for  the  public 
utilities,  such  as  water  supply,  surface  drainage 
and  sewers.  It  is  no  less  evident  that  the  needs 
of  water  purification  and  methods  to  be  em- 
ployed should  be  considered  in  relation  to  sewage 
treatment  and  disposal — and  that  garbage  dis- 
posal and  sewage  disposal  should  be  considered 
together.  There  are  many  other  questions  that 
are  related  and  should  be  given  consideration  at 
the  same  time,  even  if  not  intended  to  be  pro- 
vided for  together,  so  that  when  provided  for 
they  may  fit  in  as  harmonious  parts  of  a  well- 
planned  municipal  unit;  and  the  construction  of 
the  parts  may  be  carried  on  progressively,  al- 
ways aiming  at  a  future  result  by  practical  means, 
within  the  reasonable  capacity  and  resources  of 
the  city. 

The  "reform  of  the  city  plan"  would  be  a  bet- 
ter term  perhaps  than  "city  planning/'  which  has 

1 1 


Sanitation  of  Cities 

of  late  gained  such  currency  as  to  become  fashion- 
able. It  is  seldom  that  new  cities  are  built  from 
the  ground  up.  Occasionally  there  is  an  op- 


PARIS,  FRANCE 
River  Seine,  near  the  Louvre 

portunity  for  a  L'Enfant  to  lay  out  a  great 
capital,  but  this  is  seldom.  The  work  of  the  city 
planner  is  chiefly  the  work  of  the  reformer — and 
his  work  in  these  days  is  very  necessary. 

Existing  cities  require  replanning  in  many 
ways  in  order  that  they  may  be  made  sanitary, 
convenient,  efficient  and  beautiful.  The  sites  of 
many  cities  owe  their  selection  to  the  avenues  of 
trade  and  commerce,  and  their  street  design  prin- 
cipally to  the  land  speculator..  A  veritable  wil- 
derness may  in  a  few  years  become  the  center  of 
a  vast  population,  a  metropolis,  with  its  people 
gathered  from  every  quarter  of  the  earth. 

Sanitation  is  seldom  considered  at  the  begin- 

12 


(Seneral  Considerations 

ning  of  such  a  city  and,  as  its  need  becomes  im- 
perative, makeshift  design  is  resorted  to,  usually 
offered  by  unskillful  or  unqualified  persons.  Of 
the  American  cities  it  may  too  often  be  said  that 
they  "just  grew/'  were  not  founded  by  any  one 
in  particular,  and  had  no  city  plan.  Hence  it  is 
that  existing  streets  do  not  properly  provide  for 
existing — not  to  mention  future — traffic,  and  that 
in  the  layout  of  these  streets  insufficient  con- 
sideration was  given  to  the  requirements  of  sewer- 
age and  drainage. 

In  some  cities,  where  much  money  has  been 
expended  on  streets  and  architectural  embellish- 


A  TIDAL  STREAM  ON  LONG  ISLAND 

Undeveloped  and  insanitary  but  not  unhappy  looking.    Oyster  beds  nearby 
caused  typhoid  fever  on  several  occasions 

ments,  the  sanitary  condition  of  the  river  or 
harbor,  upon  which  the  wealth  of  the  community 
primarily  depends,  has  been  neglected  and  the 

13 


Sanitation  of  Cities 

water  has  already  become,  or  is  rapidly  becom- 
ing, grossly  polluted.  Plants  for  high  grade 
sewage  treatment  have  been  introduced  at  great 
expense  by  some  cities  which  do  not  even  purify 
their  drinking  water — a  far  greater  necessity— 
since  no  possible  grade  of  sewage  treatment  can 
render  river  water,  mixed  with  sewage  plant 
effluent,  desirable  or  really  safe  for  human  con- 
sumption. There  frequently  is  a  general  absence 
of  scale,  or  perspective,  in  these  improvements, 
and  with  the  best  intentions  in  the  world  the  re- 
sult is  much  wasteful  expenditure. 

The  principles  that  should  control  in  the  "re- 
form of  a  city  plan/'  particularly  those  relating 
to  sanitary  requirements,  are  of  interest  to  every- 
one. Much  has  been  written  by  experts  on  this 
subject,  especially  by  English  and  European  en- 
gineers and  architects,  and  even  by  some  of  our 
own  countrymen.  Unfortunately  these  writings 
are  scattered  through  many  pages  of  the  technical 
magazines,  sometimes  in  a  foreign  language  or 
in  expensive  text  books  not  readily  available  to 
the  lay  reader  for  whom  this  paper  is  primarily 
intended. 


CHAPTER  II 

THE  CITY  PLAN  AND  THE  SANITARY 
UTILITIES 

IT  is  obvious  that  the  street  plan  of  a  city  should 
not  only  provide  for  traffic,  and  the  various  other 
more  apparent  purposes  for  which  streets  and 
highways  are  provided,  but  also  for  economy  and 
efficiency  in  the  installation  and  operation  of 
the  important  sanitary  utilities — water  supply 
and  sewerage — in  order  that  the  water  may 
travel  the  shortest  distance  practicable  from  the 
main  supply  to  the  consumer,  and  the  sewage 
the  shortest  practicable  distance  to  the  point  of 
disposal  without  such  loss  in  velocity  as  would 
cause  deposits  in  the  sewers.  But  the  city  plan- 
ner, whose  mind  is  usually  occupied  with  city 
beautification,  and  the  needs  of  street  traffic, 
often  overlooks  these  sanitary  improvements; 
and,  in  reforming  or  improving  the  street  plan, 
often  neglects  the  opportunity  to  design  the  new 
streets  with  the  view  of  more  efficient  sewers, 
that  would  afford  a  much  more  rapid  concentra- 

15 


i6 


Gbe  City  plan  anb  tbe  Sanitary  TUtiUtte* 

tion  of  the  flow,  and  lead  the  sewage  to  the  main 
outfall  before  the  suspended  solids  had  time  to 
pass  into  solution. 

The  first  principles  of  street  design  require  the 
proper  accommodation  of  these  utilities.  This 
indeed,  should  be  considered  as  one  of  the  main 
objects,  if  not  the  most  important  object,  to  be 
obtained  by  the  redesign  and  improvement  of  the 
street  system.  It  is  not  necessary  in  this  connec- 
tion to  go  into  detail  concerning  the  architectural 
and  engineering  features,  as  to  width,  etc.,  of 
streets.  The  city  planner  will  not  neglect  to  take 
proper  care  of  this  feature  of  his  work. 

The  street  plan  should  be  economical,  and  con- 
form to  the  topography,  with  the  lines  made  as 
simple  as  possible.  Various  forms  of  plans  are 
recognized — as  the  radial  and  circumferential,  the 
rectangular  or  "gridiron  plan/'  and  a  combina- 
tion of  these  plans.  In  some  instances,  plans  are 
used  greatly  resembling  those  of  European  cities 
of  the  Middle  Ages,  which  have  in  recent  years 
been  replanned  with  circumferential  streets,  re- 
placing old  lines  of  city  walls  now  removed.  In 
others,  new  streets  are  controlled  mainly  by  prop- 
erty lines.  But  whatever  the  scheme  or  form,  the 
effect  on  sanitary  utilities  should  be  given 
primary  consideration;  and  before  the  improved 
street  plan  is  fixed  upon,  the  design  of  the  sanitary 
system  should  be  completely  worked  out  by  ex- 
perts, and  the  proposed  plan  amended,  if  neces- 


JS 

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18 


<EU$  plan  anfc  tbe  Sanitary  TDUUitiee 

sary,  to  conform  to  the  requirements  of  these 
utilities. 

The  sanitary  requirements  having  been  pro- 
vided for,  the  architectural  judgment  of  the  city 
planner  can  be  trusted  to  produce  fine  effects — by 
a  proper  treatment  of  existing  streets,  with  parks 
introduced  where  possible,  or  with  fine  buildings 
at  focal  points.  This  is  that  portion  of  the  de- 
signer's work  which  is  appealing  to  the  layman. 
It  is  the  finished  side  of  the  embroidered  fabric, 
showing  the  beauty  of  the  design,  while  the 
under  side — or  seamy  side — remains  hidden,  and 
the  hard  work  expended  on  planning  to  meet  the 
requirements  of  traffic  and  commerce,  as  well  as 
sanitary  and  other  utilities,  is  seldom  seen  or  ap- 
preciated by  the  pleased  beholder. 

The  appearance  of  the  streets  of  a  city  is  best 
shown  by  pictures.  This  is  also  true  of  parks, 
water  fronts  and  seaside  resorts,  which  may  con- 
stitute some  of  the  very  important  parts  of  a  city 
design. 

American  city  designers  have  been  especially 
successful  in  preserving  and  accentuating  the  in- 
timate character  of  the  city  intrusted  to  their  pro- 
fessional care.  It  is  of  interest  to  compare  the 
street  views  of  various  cities  and  observe  their  in- 
dividual characteristics. 

In  the  old  world  this  quality  has  grown  through 
ages  of  history,  and  gives  to  each  city  an  air  of 
personal  distinction;  especially  is  this  the  case 

19 


20 


City  pan  ant)  tbe  Sanitary  ^Utilities 

with  European  cities  which  have  not  suffered  or 
benefited  by  extensive  replanning.  In  Europe, 
for  instance,  much  that  has  been  done  in  the  line 
of  very  necessary  civic  rebuilding  has  involved 
extensive  destruction  of  old  buildings,  and  recon- 
struction on  lines,  not  unlike  our  rapidly  advanc- 
ing western  cities,  which,  while  partaking  of  the 
general  character  of  newness  belonging  to  our 
country,  are  not  quite  in  harmony  with  the  dis- 
tinction and  personality  of  the  ancient  European 
city.  Moreover,  the  new  structures  and  plans 
have  a  remarkable  sameness,  which  to  a  great  ex- 
tent deprives  each  newly  planned  and  recon- 
structed city  of  its  individuality.  On  the  other 
hand,  it  must  be  admitted  that  in  a  material  sense, 
the  replanned  cities  are  unrivaled.  The  provi- 
sions made  for  health,  prosperity,  and  efficiency, 
are  of  the  very  best,  and  these  include  the  sanitary 
systems  provided,  as  well  as  the  more  apparent 
features  of  the  plan. 


21 


22 


CHAPTER  III 

WATER  SUPPLY  AND  REMOVAL 
OF  SEWAGE 

THE  sanitary  utilities  which  are  especially  neces- 
sary in  a  city  are  water  supply  and  sewage  collec- 
tion and  disposal.  There  are  other  sanitary  utili- 
ties, such  as  those  for  the  removal  and  treatment 
of  waste  materials — from  kitchens,  etc.,  and  the 
sweepings  from  streets;  but  these  do  not  require 
the  installation  of  special  structures  underground 
in  every  street,  and  are  seldom  considered  in  con- 
nection with  the  city  plan. 

The  supply  of  water,  and  its  removal  and  dis- 
position when  it  has  become  polluted  by  human 
use,  constitute  a  problem  that  cannot  fairly  be 
divided.  The  structures  required  form  one  vast 
machine,  consisting  of  two  principal  parts — the 
one  carrying  in  the  pure  water,  and  the  other 
carrying  out  the  polluted  water,  or  sewage,  and 
providing  for  its  disposal. 

The  water  supply  and  sewage  removal  struc- 
tures may  be  described  as  a  single  system,  since 

23 


Gbe  Sanitation  of  Cities 

neither  water  supply,  nor  sewerage,  constitutes  by 
itself  a  complete  sanitary  utility  without  the 
other — which  system  may  be  considered  as  prop- 
erly consisting  of  the  following  parts : 


Source  of  supply 

Collection 

Preparation 

Storage 

Distribution 


Service  to 
Consumer 


Plumbing  fixtures 
Sewerage  system 
Sewage  treatment 
Effluent  discharge 
Final  disposal 


Thus  it  will  be  observed  that  the  operation  of 
this  great  sanitary  system  is  continuous  from  the 
source  of  the  water  supply  to  final  discharge; 
and  a  further  consideration  will  reveal  the  inter- 
dependence of  every  part  above  indicated,  on 
every  other  part  in  the  system.  In  fact,  the  rela- 
tion of  part  to  part  is  self-evident;  but  there  are 
many  qualifying  circumstances  that  enter  into 
the  problem,  when  it  is  examined  in  detail.  Local 
conditions,  a  term  so  often  used  by  sanitary  en- 
gineers, supply  most  of  the  qualifying  factors, 
and  are  of  great  importance  in  every  instance  of 
actual  design ;  but  in  a  broad  generalization  such 
as  this  study  intends,  average  conditions  only  can 
be  considered.  The  portrayal  of  general  truth  is 
intended,  rather  than  the  delineation  of  specific 
instances. 

The  sources  of  water  supply  have  a  direct  re- 
lation to,  and  bearing  upon,  the  last  step  in  the 
chain:  namely,  sewage  treatment  and  disposal. 
If  it  is  asked  to  what  extent  water  should  be 

24 


TKflater  Supply  anb  1Remo\>al  of  Sewage 

treated,  or  purified,  in  preparation  for  human  con- 
sumption, the  answer  involves  the  further  ques- 
tion— "How  impure,  or  polluted,  is  the  source  of 


BIRMINGHAM,  ENGLAND 

Outfall  of  treated  sewage  from  treatment  plant.    The  treated  sewage  from 

this  plant  is  greater  in  volume  than  the  ordinary  flow  in  the 

river  into  which  it  is  discharged  and  is  much  purer 

supply?"  If  on  the  other  hand,  it  is  asked  to 
what  extent  sewage  should  be  treated,  the  answer 
involves  a  reply  to  the  question — "Will  the  efflu- 
ent by  any  means  find  its  way  into  the  source  of  a 
water  supply?" 

Obviously,  if  a  source  of  supply  is  free  from  all 
danger  of  sewage  pollution,  it  need  not  be  treated 
to  remove  the  danger  of  causing  diseases  which 
commonly  arise  from  this  pollution. 

25 


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Mater  Supply  anb  IRemovml  of  Sewage 

There  are  other  reasons,  however,  on  account 
of  which  treatment  may  still  be  required — such 
as  hardness,  discoloration,  etc.  It  is  no  less  evi- 


DAYTONA,  FLORIDA 

Foot   bridge   across   the   Halifax    River,   immediately  below   R-W  sewage 
treatment  plant  into  which  the  treated  sewage  is  discharged 

dent  that  sewage  treatment  will  need  only  to  be 
provided  for  the  purpose  of  keeping  a  waterway 
in  a  sanitary  condition,  if  the  water  therefrom  is 
to  be  used  for,  or  find  its  way  into,  a  source  of 
water  supply. 

The  treatment  of  water,  for  water  supply  pur- 
poses, is  one  thing,  and  the  treatment  of  sewage 
quite  another.  On  this  subject  there  is  much  mis- 
understanding in  the  public  mind.  Many  people, 
not  accurately  informed,  appear  to  think  that  the 
treatment  of  water  for  drinking,  and  the  "puri- 
fication" of  sewage  to  secure  practically  the  same 
grade  of  purity,  are  equally  feasible  and  quite 
simple.  There  could  be  no  greater  mistake. 

27 


Sanitation  of  Cities 

Water  for  drinking  purposes  usually  carries  but 
little  organic  impurity,  in  comparison  with  sew- 
age, and  is  very  readily  purified,  and  the  plants 


FITCHBURG,  MASSACHUSETTS 
A  large  Imhoff  tank  sewage  treatment  plant 

provided  for  the  purpose  are  reliable  and  efficient. 
Sewage  practically  cannot  be  purified  by  any 
known  process  that  is  reliable.  Beyond  a  reduc- 
tion in  suspended  matters,  and  a  partial  oxida- 
tion of  dissolved  solids,  the  treatment  of  sewage 
produces  negative  results.  When  there  is  danger 
of  sewage  pollution,  and  no  other  source  of  water 
supply  is  available,  water  purification  affords 
about  the  only  solution  of  the  problem. 

It  should  be  understood  that  sewage  treatment 
can  not  replace  water  purification;  but  water 
purification  will  give  reasonable  protection  from 
water-borne  disease-germs,  whether  we  have 
sewage  treatment  or  not.  Therefore,  the  real 
purpose  of  sewage  treatment  should  usually  be 

28 


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Sanitation  of  Cities 

limited  to  the  prevention  of  a  nuisance  in  the 
vicinity  of  the  discharging  sewage  effluent,  in 
the  waterway  which  it  enters.  It  is  seldom  proper 
or  advisable  to  use  water  that  contains  sewage  as 
drinking  water,  even  if  treated  by  a  purification 
plant.  It  is  unwise  to  treat  sewage  with  a  view  to 
turning  it  into  drinking  water. 

Water  purification  should  be  as  perfect  as  pos- 
sible, as  this  is  the  only  real  protection  against 
water-borne  diseases  which  may  lurk  in  any 
natural  surface  water.  Sewage  treatment  should 
be  as  simple  as  possible,  and  the  extent  of  treat- 
ment no  greater  than  sufficient  to  maintain  satis- 
factory sanitary  and  aesthetic  conditions  in  the 


MIAMI,  FLORIDA 
Royal  Palm  Park,  Biscayne  Bay 

local  waterway  receiving  the  sewage.  Much 
money  has  been  wasted  on  elaborate  sewage 
treatment  plants,  designed  to  attempt  the  "puri- 

3° 


Gbe  Sanitation  of  Cities 

fication"  of  sewage,  or  protect  water  supplies 
"lower  down"  on  a  river,  to  an  extent  uncalled  for 
by  local  requirements. 

Sewers  must  of  necessity  discharge  into  rivers 
-they  will  always  do  so — and  rivers  should  be 
avoided  if  possible  as  sources  of  water  supply, 
but  kept  in  such  sanitary  condition  that  fish  life 
will  be  protected;  and  there  should  be  no  visible 
nuisance.  Further  protection  than  this  is  seldom 
called  for,  or  justifiable. 

A  simple  and  reliable,  positively  operating 
sewage  disposal  plant,  designed  to  meet  the  actual 
sanitary  needs,  is  always  better  than  a  compli- 
cated plant  designed  to  give  a  greater  degree  of 
treatment  than  is  necessary,  that  within  a  year 
or  two  may  be  abandoned  because  of  operating 
difficulties,  or  a  higher  degree  of  skill  required 
in  management  than  is  ordinarily  available. 

In  the  selection  of  water  supplies,  quality  and 
quantity  of  water  must  be  considered  first, — then 
the  expense  of  development,  etc.  The  sources  of 
the  water  supplies  used  by  most  of  the  larger 
American  cities  are  shown  by  the  following  state- 
ment: 

Wells  of  various  kinds 40  per  cent 

Ponds,  lakes  and  springs 25 

Rivers  and  streams 24 

Mountain  streams 1 1 

Too     " 

It  has  been  estimated  that  about  4000  Ameri- 
can cities  and  towns  are  provided  with  public 

32 


TKHater  Supply  anb  IRemoval  of  Sewage 

water  supplies.  Most  of  these  are  relatively  small 
installations,  and  the  majority  obtain  their  sup- 
plies from  wells.  The  amount  of  well  water  ob- 
tained in  some  places  is  remarkably  large — one 
supply  from  the  sands  of  Long  Island  yielding 
daily  up  to  100,000,000  gallons,  with  a  supply  per 
square  mile  of  750,000  gallons. 

Water  taken  from  wells  is  usually  excellent, 
clear,  pure  and  colorless,  requiring  no  purifica- 
tion; but  it  may  be  hard,  and  some  well  waters 
contain  various  inorganic  matters  in  solution 
which  cause  a  slight  trace  of  color.  This,  as  well 
as  excessive  hardness,  can  be  removed  by  ap- 
propriate treatment.  Water  supplies  obtained 
from  deep  wells  seldom,  if  ever,  are  in  danger  of 


ORMOND,  FLORIDA 
View  of  a  park 

sewage  pollution,  even  where  the  water-bearing 
sands  are  located  within  fairly  populous  districts; 
as  is  the  case  with  the  Long  Island  supply  before 

33 


Sanitation  of  Cities 

mentioned,  on  the  drainage  area  of  which  dwells 
a  large  population,  in  several  towns  of  consider- 
able size. 

Lake  supplies  are  much  more  subject  to  pollu- 
tion than  well  supplies — and  in  almost  every 
case  sanitary  safety  demands  water  purification 
where  water  from  these  sources  is  used  for  human 
consumption.  Buffalo,  Cleveland,  Chicago,  De- 
troit, Duluth,  Erie,  and  Milwaukee,  as  well  as 
many  other  cities  and  towns,  use  lake  water. 
Long  intakes  in  many  instances  are  provided  at 
great  cost,  to  obtain  supplies  far  enough  from  the 
shore  to  avoid  local  pollution. 

The  Great  Lakes  receive  the  sewage  and  storm 
washings  from  many  urban  surfaces,  and  millions 
of  people  depend  upon  the  lake  water  for  drink- 
ing and  other  purposes.  To  improve  waterfront 
property,  and  prevent  local  nuisance,  sewer  out- 
lets are  also  extended  outward  from  the  shores; 
so  that  a  race  seems  to  be  on  between  the  extend- 
ing water  intakes  and  the  sewer  outfalls.  Ex- 
perts are  employed  to  select  locations  for  water 
intakes,  at  points  where  prevailing  winds  and 
currents  will  not  carry  the  polluted  water  from 
the  city  streets  and  sewers.  In  some  places,  the 
cry  goes  up  that  the  sewage  should  be  so  com- 
pletely treated  as  to  prevent  all  danger  of  pollu- 
tion entering  the  water  supply,  and  methods  of 
treatment  are  recommended  which,  notwith- 
standing their  great  cost,  when  installed,  fail  to 

34 


Mater  Supply  anb  1Remo\>al  of  Sewage 

accomplish  this  purpose.  For,  as  has  been  often 
pointed  out,  no  method  of  sewage  treatment  af- 
fords a  means  capable  of  turning  sewage  into  an 
acceptable  drinking  water. 


BALTIMORE,  MARYLAND 
Settling  or  septic  tanks  in  operation 

Impounding  reservoirs  are  usually  necessary 
with  any  system  of  water  supply  other  than  a 
source  derived  from  driven  wells,  or  from  large 
lakes.  Storage  greatly  decreases  the  danger  of 
bacterial  pollution,  especially  from  pathogenic 
germs;  affords  opportunity  for  suspended  mat- 
ters to  settle;  and  enlists  the  bleaching  effects  of 
sun  and  air  in  the  removal  of  any  undesirable 
color.  Its  main  purpose,  however,  is  to  provide 
an  adequate  reserve  supply;  especially  where  the 
spring  and  fall  rains  are  heavy  and  the  rainfalls 
of  the  other  seasons  are  insufficient  for  the  pe- 
riods in  which  they  fall. 

35 


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36 


Mater  Suppl?  anb  IRemoval  of  Sewage 

According  to  most  authorities,  it  is  a  well  estab- 
lished fact  that  sewage  bacteria,  especially  of  the 
B.  coli  group,  die  off  rapidly  in  clear  cold  water, 
while  the  aerobic  bacteria,  natural  to  water,  are 
not  so  adversely  affected,  and  remove  any  trace 
of  organic  pollution  which  may  chance  to  be 
present.  The  number  of  bacteria  present  is 
evidence,  or  even  a  direct  index,  of  the  amount  of 
bacterial  food  supply  existing  in  the  water  and, 
if  the  storage  is  properly  regulated  by  successive 
basins,  a  natural  purification  takes  place,  which 
often  renders  further  treatment  unnecessary.  For 
example,  at  Lawrence,  Mass.,  the  bacterial  re- 
duction in  a  two  weeks'  passage  through  the 
city  reservoirs  exceeds  93  per  cent  on  the  aver- 
age. At  Washington,  D.  C,  in  one  week's  passage 
through,  the  reduction  exceeds  90  per  cent,  and 
at  the  Boonton  reservoir,  a  part  of  the  supply  of 
Jersey  City,  N.  J.,  a  six  months'  storage,  or  pas- 
sage through,  effects  a  removal  of  99  per  cent  of 
the  bacterial  pollution. 

There  is,  however,  a  limit  to  the  time  during 
which  storage  is  advisable.  If  it  is  too  long, 
stagnation  occurs,  especially  in  the  bottom  lay- 
ers of  the  reservoir,  accompanied  by  various 
growths  common  to  stagnant  ponds — organic 
matter  is  deposited  and  dissolves,  bacteria  in- 
crease, as  well  as  other  low  forms  of  life  which 
give  a  bad  taste  to  the  water,  and  deprive  it  of 
dissolved  oxygen.  Aeration  and  filtration  are 

37 


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Heater  Supply  anb  IRemoval  of  Sewage 

both  used  singly  or  combined  to  correct  the  dif- 
ficulty referred  to.  The  odor  and  bad  tastes  due 
to  stagnant  water  are  not  as  troublesome  as 
those  from  certain  forms  of  animal  and  vegetable 
life,  commonly  known  as  algae.  The  tastes  and 
odors  referred  to  are  caused  by  the  essential  oils 
which  these  organisms  secrete  during  their  z 

growth.     They   fortunately   exist   only   during         <  jjj 
the  summer  months,  and  can  be  controlled  by 
minute  amounts  of  certain  chemicals,  and  by  a 
proper  regulation  of  the  reservoirs. 

Rivers,  next  to  the  Great  Lakes,  afford  the 
largest  supplies  of  fresh  water  available,  and  are         o 
more  subject  to  pollution  than  the  other  sources 
of  water  supply.     River  water  usually  requires         |   £ 
purification  in  order  that  its  use  may  be  free  from 
danger. 

As  has  often  been  pointed  out  by  sanitarians, 
one  of  the  first  facts  to  be  recognized  in  connec- 
tion with  the  discharge  of  sewage  into  a  river,  and 
the  use  of  the  water  for  a  public  supply,  is  that  no 
practical  method  of  sewage  purification  will  re- 
move absolutely  all  danger  of  pathogenic  germs. 
It  is  therefore  better  to  obtain  other  supplies  if 
possible. 

The  primary  object  of  a  sewage  disposal  plant 
is  to  remove  the  offensive  matters  and  treat  the 
sewage  to  the  highest  degree  commensurate  with 
requirements  of  the  local  conditions.  Public 
waterways  will  always  continue  to  receive  the 

39 


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40 


Wlater  Supply  anb  IRemoval  of  Sewage 

sewage  of  cities,  and  the  one  thing  which  remains 
to  be  done  is  to  see  that  sewage  wastes  are  made 
unobjectionable  before  their  discharge.  This  is 
practically  all  that  any  community  should  be  re- 
quired to  do. 

The  ideal  state  of  affairs  toward  which  Ameri- 
can sanitarians  are  working,  is  to  permit  all  cities 
to  discharge  their  sewage  into  the  nearest  stream, 
but  require  them  first  to  treat  it  to  a  degree  which 
will  preclude  the  establishment  or  maintenance 
of  obnoxious  conditions  in  the  stream.  Rarely 
are  two  problems  of  this  kind  found  to  be  alike. 
The  sewage  of  some  cities  should  be  treated  to  a 
far  greater  degree  than  that  of  others,  dependent 
on  the  initial  pollution  of  the  stream,  its  mini- 
mum volume  and  velocity  of  discharge,  and  the 
distance  to  the  next  city  or,  more  exactly,  to  the 
intake  of  the  next  water  supply. 


• 


I" 

3 


CHAPTER  IV 

THE  PURIFICATION  OF  WATER 
SUPPLIES 

THE  treatment  of  water  to  improve  its  appear- 
ance and  quality  has  been  undertaken  in  various 
ways  for  many  years.  In  ancient  times,  the  most 
important  method  seems  to  have  been  storage; 
and  from  observing  the  effect  of  natural  filtration 
through  sands,  along  the  shores  of  streams,  it  is 
not  improbable  that  some  form  of  filtration  was 
employed  at  a  very  early  date.  The  Chinese, 
from  very  ancient  times,  have  used  sulphate  of 
alumina  for  the  purpose  of  improving  the  appear- 
ance of  water.  In  modern  days,  the  first  large 
filter  appears  to  have  been  placed  in  service  on 
the  water  supply  of  London,  England,  in  1829. 
After  the  cholera  epidemic  of  1849,  the  filtration 
of  the  entire  supply  of  that  city  was  made  com- 
pulsory. But  the  existence  of  disease-bearing 
bacteria,  or  "germs/'  was  unknown,  and  the  most 
important  office  of  filtration  was  not  appreciated 
until  long  after  this  date. 

43 


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44 


purification  of  Mater  Supplies 

The  life-work  of  the  immortal  Pasteur  demon- 
strated the  germ  theory  of  disease,  and  gave  a 
new  meaning  to  water  purification,  as  well  as  to 
all  branches  of  sanitary  science  derived  from 
biology. 

The  work  of  Koch  on  the  causes  of  cholera, 
which  created  the  technique  of  bacteriological 
study,  and  included  the  discovery  of  the  cholera 
germ,  or  bacillus;  that  of  Eberth  and  Gaffky 
on  typhoid  fever,  with  the  discovery  of  its 
specific  bacillus;  and  that  of  the  Bacillus  coli 
by  Escherich,  gave  a  new  purpose  to  water 
purification,  and  sewage  treatment.  These  dis- 
coveries late  in  the  last  century  led  to  the  wide- 
spread adoption  of  water  filtration,  with  the  re- 
sult that  typhoid  deaths  were  reduced  by  this 
means  in  many  of  the  great  European  cities,  to  a 
very  small  fraction  of  their  former  number.  This 
work  also  led  sanitarians  to  conclude  that,  with 
a  universal  adoption  of  this  means  of  protection, 
typhoid,  cholera,  and  other  water-borne  diseases 
would  in  time  entirely  disappear  from  the  death 
statistics  of  nations. 

Water  purification  was  an  English  invention. 
The  first  filters,  as  mentioned  before,  were  placed 
in  1829  and  the  whole  supply  of  London  was 
ordered  filtered  in  1849 — following  which  the  in- 
troduction of  filters  in  other  cities  made  rapid 
progress. 

In  1860,  English  engineers  installed  the  first 

45 


purification  of  Mater  Supplies 

filters  on  the  Continent  at  Altona,  Germany,  later 
at  Berlin,  and  at  several  other  German  cities.  The 
Altona  filters  are  famous  as  having  prevented  the 
cholera  epidemic  from  spreading  to  that  city  in 
1892,  although  it  raged  in  Hamburg,  an  adjoining 
city  which  was  not  served  with  filtered  water. 
Both  of  these  cities  at  that  time  took  their 
water  supply  from  the  Elbe  River  into  which  also 
they  discharged  their  sewage,  without  treatment. 
Altona  filtered  its  water  but  Hamburg  did  not. 
At  present,  both  cities  filter  their  water  supplies 
but  neither  of  them  finds  it  necessary  to  go  further 
with  sewage  treatment  than  medium  fine  screen- 
ing. The  Hamburg  sewage  screen  plant  has 
screens  with  A  inch  clear  openings.  Altona 
uses  coarse  screens  for  part  of  its  sewage  dis- 
charge, but  for  the  major  part  provides  no  treat- 
ment whatever,  depending  entirely  on  water  puri- 
fication for  the  safety  of  its  water  supply. 

Out  of  the  English  practice  two  types  of  filters 
have  been  developed  for  water  treatment.  These 
are  usually  named  from  their  most  salient  fea- 
tures, slow  sand  filters,  and  rapid  sand  filters.  The 
earlier  installations  were  all  slow  sand  filters. 

A  slow  sand  water  filter  consists  of  a  watertight 
basin,  the  floor  of  which  is  provided  with  under- 
drains,  with  a  covering  of  about  one  foot  of  coarse 
gravel,  over  which  are  placed  several  feet  of  clean 
sand.  To  prevent  freezing,  a  roof  usually  carried 
on  groined  arches  is  placed  over  the  basin, 

47 


Sanitation  of  Cities 

The  drains  referred  to,  consist  of  a  main  col- 
lector with  lateral  branches  at  regular  intervals 
— graded  stone  or  coarse  gravel  is  usually  placed 


PARIS,  FRANCE 

A  park-like  development  of  the  irrigated  field  from  the  sewage 
treatment  plant  by  broad  irrigation 

on  the  bottom,  sufficiently  deep  to  cover  the 
lateral  drains.  Over  this,  the  sand,  which  is  the 
filtering  material,  is  placed  to  a  depth  of  three  or 
four  feet. 

When  ready  for  service,  water  is  permitted  to 
enter  the  filter  to  a  depth  over  the  sand  of  about 
three  feet,  and  percolates  through  the  sand  at  a 
daily  rate  of  about  ten  cubic  feet  per  square  foot 
of  bed,  affording  a  daily  flow  of  about  3,000,000 
gallons  per  acre  of  surface.  But  it  is  not  until 
after  several  weeks  of  operation  that  the  filter 
does  its  best  work.  By  this  time,  a  gelatinous  film 
has  formed  on  the  surface  of  the  sand,  derived 

48 


purification  of  TKHater  Supplier 

from  the  organic  matter  and  sediment  present  in 
the  unfiltered  water,  which  gives  it  its  highest  effi- 
ciency. This  film,  however,  becomes  in  time  so 
thick  that  it  clogs  the  filter,  and  the  operation 
must  be  interrupted  for  its  removal,  and  for  the 
cleansing  and  restoration  of  the  surface.  There 
are  various  ways  of  effecting  this,  some  of  them 
very  ingenious.  The  result  is  that  the  capacity  of 
the  bed  is  renewed  and  operation  again  proceeds. 
Where  the  untreated,  or  raw,  water  carries  large 
contents  of  suspended  matter,  settling  tanks  are 
used  as  a  preliminary  treatment  before  filtration. 
Filters  of  this  type  with  variations  have  been 
installed  in  many  cities  here  and  abroad,  the 


ORMOND,  FLORIDA 
View  along  the  shore  of  the  Halifax  River 

plants  in  England  being  particularly  well  known. 
Those  at  Altona  and  Hamburg  in  Germany  have 
been  mentioned.  There  are  many  others  in  that 

49 


Sanitation  of  Cities 

country.  In  Japan,  a  number  of  such  filters  have 
been  built,  those  at  Yokohama  and  Osaka  being 
noteworthy.  The  largest  filter  plant  of  this  type 
is  at  Philadelphia,  Pa.,  and  treats  water  from  the 
Delaware  River. 

Rapid  sand  filters,  as  well  as  slow  sand  filters, 
were  originally  invented  in  England.  A  chemical 
coagulant  is  always  added  to  the  water  to  be  fil- 
tered by  rapid  sand  filters,  and  preliminary  sedi- 
mentation is  usual.  The  sand  grains  are  coarser, 
and  the  bed  of  sand  is  cleaned  in  place,  by  revers- 
ing the  direction  of  flow — so  that  filtered  water  is 
forced  back  through  the  filter  bed.  The  raw 
water  is  first  clarified  by  the  addition  of  the  coagu- 
lants, and  after  sedimentation  in  a  tank,  is  passed 
to  the  surface  of  the  bed,  over  which  the  coagu- 
lant causes  the  rapid  formation  of  a  gelatinous 
film,  and  is  allowed  to  pass  downward  through 
this  and  the  sand  at  a  rate  about  forty  times 
greater  than  the  slow  sand  filter  would  permit. 
Rates  of  100,000,000  to  125,000,000  gallons  a 
day  to  the  acre  of  surface  are  usual. 

The  filters  are  usually  built  of  concrete,  each 
consisting  of  a  rather  small  unit;  embedded 
in  the  floor  of  each  is  the  underdrainage  system, 
consisting  of  perforated  pipes  or  strainer  cups,  de- 
signed to  allow  the  filtered  water  to  flow  out,  but 
to  retain  all  the  sand  and  effect  an  even  distribu- 
tion of  the  wash  water,  when  the  direction  of  flow 
is  reversed  for  cleaning,  by  which  means  the  layer 

50 


5' 


PARIS,  FRANCE 

View  shows  the  purified  stream  of  sewage  which  discharges 

into  the  river  nearby.    The  water  is  as  clear 

and  sparkling  as  spring  water 


purification  of  "Mater  Supplies 

of  dirty  material  is  broken  up  and  removed  from 
the  upper  surface  of  the  sand,  and  led  away 
through  waste  gutters  to  the  sewer.  Washing 
takes  only  from  ten  to  fifteen  minutes  and,  due  to 
the  coagulant,  a  new  film  forms  quickly.  The 
coagulants  commonly  used  are  compounds  of 
alumina  and  iron. 

Rapid  sand  filtration  has  come  into  extensive 
application  since  1885,  when  such  a  plant  was 
installed  at  Somerville,  N.J.,  attracting  much 
attention.  Since  then,  nearly  400  cities  in  vari- 
ous parts  of  the  world  have  adopted  this  method 
of  water  filtration. 

The  largest  plant  of  this  kind  is  probably  that 
of  Cincinnati,  Ohio,  with  a  daily  capacity  of  1 12,- 
000,000  gallons.  Some  of  the  noted  plants  are 
at  New  Orleans,  La.;  Hackensack,  N.  J.;  Little 
Falls,  N.  J.;  St.  Louis,  Mo.;  Louisville,  Ky.; 
Toledo,  O.;  Minneapolis,  Minn.;  Grand  Rapids, 
Mich.;  Alexandria,  Egypt;  Kyoto,  Japan;  etc. 

Among  the  cities  in  America  provided  with 
slow  sand  filters  may  be  mentioned  Washington, 
D.C.;  Albany,  N.  Y.;  Poughkeepsie,  N.  Y.; 
Philadelphia,  Pa.;  Superior,  Wis.;  and  other 
places. 

The  question  as  to  which  method,  whether  the 
slow  filtration  or  the  rapid,  is  better  for  any  place, 
depends  much  on  local  conditions.  Both  give 
good  results,  and  each  has  its  advocates.  With 
either,  the  water  consumer  is  reasonably  insured 

53 


Sanitation  of  Cities 

against  water-borne  disease,  and  is  certain  of  an 
excellent  water  for  all  purposes. 

It  should  be  noted  that  none  of  the  cities,  men- 
tioned above,  undertake  to  purify  their  sewage 
beyond  the  sanitary  requirements,  nor  beyond 
what  is  necessary  to  maintain  a  satisfactory  oxy- 
gen content  in  the  rivers  and  to  prevent  the 
formation  of  sludge  banks  and  visible  pollution. 

The  disinfection  of  water  to  remove  disease 
germs  is  frequently  resorted  to  where  the  water 
is  taken  directly  from  sources  of  supply  without 
filtration. 

The  chemicals  ordinarily  used  are  hypochlo- 
rites  of  lime  or  soda,  or  liquid  chlorine'gas.  These 


If 


LONG  BEACH,  CALIFORNIA 

Bathing  beach  adjacent  to  sewage  treatment  plant 


chemicals  are  applied  in  very  minute  quantities 
with  entire  success.  The  majority  of  American 
cities  have  at  times  used  them  with  good  results, 

54 


purification  of  Mater  Supplies 

under  special  conditions,  and  sometimes  follow- 
ing filtration. 

These  chemicals  are  also  used  to  disinfect 
treated  sewage,  when  it  is  necessary  to  render 
effluents  harmless,  in  the  protection  of  oyster 
beds,  or  to  kill  disease  germs  that  might  find  their 
way  into  the  intake  of  a  water  supply  plant  far- 
ther down-stream. 


THE  BEACH  AT  DAYTONA,  FLORIDA 
A  popular  winter  resort  having  a  modern  sewage  treatment  plant 


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56 


CHAPTER  V 
THE  SEWERAGE  SYSTEM 

• 

THREE  different  plans  or  classes  of  sewerage  sys- 
tems are  in  general  use.  Of  late  the  newly  de- 
signed intercepting  sewers  which  carry  the  out- 
fall to  a  new  point  of  final  discharge  have  come 
to  be  called  the  main  drainage.  The  method  of 
sewage  treatment  required  by  a  city  depends 
very  largely  on  the  design,  extent,  and  class  of 
sewerage  systems  installed.  Each  of  these  sys- 
tems may  be  briefly  considered,  as  follows: 

THE  COMBINED  SYSTEM 

In  this  system  all  kinds  of  sewage  and  drain- 
age are  carried  in  the  same  sewers.  There  is  ordi- 
narily but  one  sewer  in  each  street,  and  to  this  the 
street  inlets  or  basins  are  connected  to  admit  the 
storm  waters,  as  well  as  the  house  sewer  connec- 
tions, which  admit  all  domestic  wastes,  roof 
water,  yard  water,  etc. 

In  this  system  the  outfall  mains  are  of  suffi- 
cient size  to  take  care  of  the  vast  quantity  of 
storm  water  when  it  rains;  consequently  they  are 

57 


ZTbe  Sewerage  System 

so  large  that  in  dry  weather  they  act  as  settling 
tanks,  and  delay  the  velocity  of  the  domestic  or 
dry  weather  flow  sewage — which  causes  deposi- 
tion of  solids  in  the  sewer  inverts.  The  solids 
thus  deposited  remain,  and  decompose  until  a 
storm  flow  flushes  them  out.  With  this  system, 
the  sewage  in  dry  weather  loosens  much  sus- 
pended matter  during  its  passage  through  the 
sewers,  and  the  storm  flow  is  rendered  exceed- 
ingly heavy  with  decomposing  sewage  solids 
which  are  gathered  up  from  the  inverts  during 
the  first  part  of  a  storm. 

COMBINED  AND  INTERCEPTING  SYSTEM 

This  system  is  similar  to  the  foregoing  system; 
in  that  all  of  the  smaller  sewers  are  combined 
sewers;  but  to  obviate  the  trouble  caused  by  the 
dry  weather,  or  domestic  flow,  in  the  large  mains, 
and  prevent  the  deposits  therein  of  sewage  solids, 
intercepting  sewers  are  provided  to  collect  the 
dry  weather  sewage  from  the  smaller  sewers,  and 
act  to  some  extent  as  separate  sewers,  paralleling 
the  lines  of  the  large  mains.  These  interceptors 
take  off  the  dry  weather  flow  at  certain  places 
called  diversion  points,  by  gravity,  as  they  are 
usually  placed  at  a  lower  elevation. 

SEPARATE  SYSTEM 

In  this,  a  double  system  is  provided;  one  sys- 
tem for  the  storm  water,  usually  called  drainage, 

59 


4 


6o 


Sewerage  System 

and  one  for  the  sewage,  usually  called  sanitary 
sewers. 

The  cost  is  much  greater  than  the  others,  but 
the  system  is  more  efficient  and,  if  possible, 
should  be  used  rather  than  either  of  the  others; 
especially,  if  the  sewage  or  the  storm  water,  or 
both,  are  to  be  treated;  as  their  treatment  in- 
volves very  different  problems,  and  is  much  more 
economical  if  each  is  kept  separate. 

The  installation  of  the  sewerage  system,  for  a 
given  city,  has  usually  been  completed  to  a  great 
extent  before  the  city  planner,  or  replanner,  has 
been  consulted.  In  most  of  our  cities  the  sewer- 
age system,  like  the  street  system,  "just  grew" 
without  design  and  is  especially  in  need  of  ex- 
pert study,  and  complete  redesign. 

The  progress  that  modern  cities  have  made  in 
population,  commerce  and  material  prosperity, 
was  not  and  indeed  could  not  have  been  foreseen, 
even  a  few  years  ago.  In  sewer  design,  the  most 
that  was  usually  attempted  was  the  removal  of 
polluted  waters  from  the  houses  and  streets,  and 
the  discharge  thereof  into  the  nearest  waterway 
deemed  of  sufficient  size  to  carry  off  the  dis- 
charge without  causing  a  local  nuisance.  Where 
sewage  treatment  was  adopted,  the  method  was 
usually  but  little  better  than  an  experimental  ap- 
plication of  some  laboratory  results,  that  seemed 
sufficiently  promising  to  justify  a  more  extensive 
trial. 

61 


CROSSNESS,  LONDON,  ENGLAND 

Chemical  precipitation  sewage  treatment  plant 


CROSSNESS,  LONDON,  ENGLAND 

Sewage   treatment   plant   chemical   precipitation 


CHAPTER  VI 

THE  SEWAGE  TREATMENT 
PROBLEM 

DISPOSAL  of  the  wastes  of  human  life  has,  from 
the  earliest  times,  been  one  of  the  problems  of 
civilization.  As  early  as  the  ninth  century  before 
Christ,  the  Assyrians  constructed  a  sewer  to  drain 
one  of  the  palaces  of  Nimrod. 

The  Romans,  the  great  engineers  of  antiquity, 
devoted  much  attention  to  sanitation,  in  which 
they  made  steady  progress  up  to  the  fall  of  the 
empire.  The  Cloaca  Maxima,  or  Great  Sewer,  of 
Rome,  constructed  about  the  seventh  century  be- 
fore Christ,  is  still  in  use. 

With  the  advent  of  the  dark  ages,  sanitary  en- 
gineering went  the  way  of  learning  in  general,  and 
all  that  the  Romans  had  learned  seems  to  have 
been  forgotten.  Great  cities  grew  up  in  Europe, 
entirely  without  provision  for  the  disposal  of 
waste  matter,  and  in  time  inevitably  became  lit- 
erally buried  in  filth.  Great  plagues  broke  out 
again  and  again,  and  swept  like  devastating  fires 

63 


Sanitation  of  Cities 

over  mediaeval  Europe;  cities  became  vast  char- 
nel  houses,  and  the  accumulation  of  filth  almost 
surpasses  human  belief — yet  it  was  not  until  the 


LONDON,  ENGLAND 

Showing  boat  for  conveying  sewage  sludge  to  the  North  Sea 
whence  it  is  discharged 

fifteenth  century  that  faint  interest  began  to  be 
manifested  in  the  study  of  sanitation  and  not 
until  well  into  the  nineteenth  that  the  subject  be- 
gan to  be  understood.  As  late  as  1847  John 
Phillips,  one  of  the  first  engineers  to  make  an  of- 
ficial report  on  sanitary  conditions  in  London, 
stated  that  conditions  as  he  found  them  were  so 
bad  as  to  defy  description. 

In  1848,  1849,  and  from  1852  to  1854,  London 
was  devastated  by  cholera.  In  1849,  14,600 
deaths  were  recorded;  and  in  the  latter  half  of 
1854,  10,675  deaths.  The  connection  between 
the  rapid  spread  of  the  disease,  and  a  contami- 

64 


66 


Sewage  treatment  problem 

nated  water  supply,  was  readily  shown,  and  the 
result  was  an  Act  of  Parliament,  which  laid  the 
foundation  for  the  prosecution  of  plans  for  an 
adequate  sewerage  system. 

It  may  be  said  that  modern  sanitary  engineer- 
ing dates  from  the  construction  of  the  Hamburg 
sewers  by  William  Lindley  in  1842.  Since  that 
time,  rapid  progress  has  been  made  and,  particu- 
larly in  late  years,  many  millions  of  dollars  have 
been  spent  in  this  country  and  abroad,  in  the  con- 
struction of  systems  of  sewerage  and  sewage  treat- 
ment plants. 

The  serious  consideration  of  sewage  purifica- 
tion in  this  country  may  be  said  to  have  begun 
with  the  construction  of  the  chemical  treatment 
sewage  disposal  plant  at  Worcester,  Mass.,  in 
1889,  and  the  establishment  of  the  Massachusetts 
State  Experiment  Station  at  Lawrence  at  about 
the  same  time. 

Although  sewage  irrigation  was  practised  in 
ancient  Athens,  and  in  the  Far  East  for  about 
2000  years,  and  sewage  farming  was  introduced 
at  Bunzlau,  Germany,  300  years  ago,  it  was  not 
until  1850  that  the  purification  of  sewage  began 
to  attract  attention  in  England.  During  the 
period  between  1850  and  1875,  the  impetus  given 
to  sanitary  work  by  the  cholera  in  London  re- 
sulted in  the  sewering  of  many  towns,  with  conse- 
quent pollution  of  streams,  and  it  became  neces- 
sary to  develop  some  method  of  purifying  sewage. 

67 


Sanitation  of  Cities 

Sewage  may  be  treated  on  agricultural  land  to 
secure  a  more  or  less  complete  purification,  if 
sufficient  land  is  available  for  this  purpose;  or  on 
intermittently  dosed  sand  filters,  with  the  same 
end  in  view.  Here  also  the  purification  secured 
is  biological,  and  there  is  a  fairly  well  marked 
limit  beyond  which  land  or  filters  will  not  afford 
purification.  This  limit  can  be  much  enlarged  by 
preliminary  treatment.  Without  preliminary 
treatment,  land  used  by  the  method  known  as 
broad  irrigation,  as  practised  in  France  for  the 
sewage  of  Paris,  and  in  Germany  for  the  sewage 
of  Berlin,  is  capable  only  of  receiving  the  sewage 
of  from  50  to  200  persons  per  acre,  depending 
upon  the  character  of  the  soil.  Intermittent  sand 
filters,  under  similar  conditions,  will  only  provide 
for  from  250  to  1000  persons  per  acre. 

Broad  irrigation  and  sewage  farming  soon 
proved  unsatisfactory  and  sanitary  development 
leaned  in  the  direction  of  septic  tanks  and  trick- 
ling filters  as  more  intensive  methods. 

From  earliest  times  household  wastes  have 
been  carried  in  one  way  or  another  to  the  nearest 
water  course  or  river  capable  of  receiving  them 
without  causing  a  nuisance.  Primitive  as  this 
method  is,  it  is  still  one  of  the  most  practical 
methods  of  sewage  disposal,  and  is  generally 
known  as  "Disposal  by  Dilution/' 

This  method  answers  the  requirements  as  long 
as  the  proper  conditions  are  maintained — that  is, 

68 


Sewage  {Treatment  problem 

as  long  as  the  volume  of  water  is  sufficiently  great 
in  proportion  to  the  amount  of  waste  allowed  to 
pass  into  it.  But  with  the  rapid  growth  of  cities, 
the  pollution  of  waterways  and  harbors  becomes 
a  serious  problem,  and  the  development  of  meth- 
ods of  sewage  treatment  has  been  mainly  with  the 
object  of  preparing  sewage  for  dilution,  so  that 
the  streams  receiving  the  effluent  can  safely  take 
care  of  the  burden  of  self-purification. 

If  the  sewage  is  discharged  into  a  sufficiently 
great  volume  of  water,  say  3%  to  4  cubic  feet 
per  second  of  flow  per  1000  persons  contributing 
sewage,  as  provided  for  by  the  Chicago  Drainage 
Canal,  no  treatment  is  considered  necessary,  as 
the  water  will  in  time  effect  complete  purification 
by  biological  agencies,  in  the  presence  of  the  dis- 
solved oxygen  content  of  the  stream.  But  even 
in  this  case,  sanitary  standards  require  the  re- 
moval of  floating  and  suspended  matter  from  the 
sewage.  Where  the  volume  of  flow  per  second  in 
the  waterway  falls  below  the  above  requirements 
per  capita,  some  other  form  of  sewage  treatment 
is  usually  resorted  to,  and  the  extent  of  treat- 
ment required  will  differ  in  each  case  with  the 
volume  of  water  available  for  dilution  of  the 
effluent,  with  the  local  conditions,  as  well  as  with 
other  factors  which  enter  into  the  problem. 

Obviously  where  streams  or  other  waterways 
will  not  afford  sufficient  dilution  to  effect  biolog- 
ical purification,  without  causing  exhaustion  of 

69 


yo 


Sewage  treatment  problem 

dissolved  oxygen  from  the  water,  or  where  the 
formation  of  banks  of  deposited  sewage  solids 
might  cause  a  nuisance,  even  if  the  water  for  dilu- 
tion were  sufficient,  preliminary  or  preparatory 
sewage  treatment  is  necessary.  Also,  where  the 
disposal  is  on  land,  or  by  means  of  sand  filters,  in 
order  that  the  polluting  effect  of  the  sewage  may 
be  so  far  diminished  that  a  much  greater  quantity 
can  be  disposed  of  per  acre  by  these  methods,  pre- 
paratory treatment  is  required  for  the  same 
reason. 


CHAPTER  VII 

THE  BIOLOGICAL  TREATMENT 
OF  SEWAGE 

SEWAGE  treatment  is  seldom  undertaken  at  a 
sewage  disposal  plant,  regardless  of  the  method 
employed,  with  the  object  of  producing  actual 
sewage  purification.  This  would  indeed  be  a  very 
costly  matter,  and  fortunately  is  required  only 
under  exceptional  conditions,  and  is  practically 
restricted  to  the  method  known  as  sand  filtration. 
Purification  is,  however,  the  end  or  result  which 
every  method  has  in  view.  As  this  may  seem  a 
paradoxical  statement  unless  further  explained, 
it  should  be  pointed  out  that  the  purification  of 
polluted  waters  observed  in  nature  is  strictly  a 
biological  process;  and  that  considerable  time  is 
required  for  its  complete  action,  whether  by  fil- 
ters, on  land,  or  by  dilution. 

The  object  sought  by  sewage  treatment  is  the 
removal  to  a  greater  or  lesser  extent,  as  condi- 
tions require,  of  the  floating  matters,  settling  mat- 
ters, non-settling  putrescible  matters,  and  ob- 
jectionable bacteria.  Trade  wastes,  which  are 

73 


o 
z 


C3 
O 

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U 


74 


Biological  {treatment  of  Sewage 

the  spent  liquors  and  waste  material  resulting 
from  the  operations  of  various  industries,  must 
also  be  considered  in  the  treatment. 

Floating  matters  may  be  broken  up  and  settled, 
and  partially  removed  by  baffles  placed  in  grit 
catches,  etc.  Various  methods,  such  as  tanks 
and  fine  screens,  have  been  devised  for  the  re- 
moval of  floating  and  settling  matters,  which  tend 
to  dissolve,  or  break  up  into  finely  divided  sus- 
pended solids,  usually  called  "colloids/'  if  not 
promptly  taken  from  the  liquid  part  of  the  sew- 
age; and  thus  give  rise  to  the  presence  of  non- 
settling  putrescible  matters,  which  are  very  dif- 
ficult to  remove.  These  cause  the  most  costly 
part  of  sewage  treatment,  if  their  removal  must 
be  effected.  But  they  are  the  part  of  the  sewage 
matters  that  are  most  rapidly  disposed  of  by 
biological  oxidation  in  rivers,  and  on  land,  if 
they  are  not  present  in  quantities  great  enough  to 
produce  oxygen  exhaustion.  Objectionable  bac- 
teria are  such  as  may  cause  human  disease;  their 
removal  is  effected  usually  by  some  form  of  chem- 
ical disinfectant  applied  to  the  treatment  plant 
effluent. 

The  removal  of  settling  matters  from  polluted 
waters  and  sewage  has  for  ages  been  accomplished 
by  means  of  tanks.  Of  these,  two  general  classes 
should  be  mentioned:  tanks  which  depend 
merely  on  detention  of  the  sewage,  and  sedimen- 
tation, which  are  the  oldest  form  used;  and  tanks 

75 


Biological  {Treatment  of  Sewage 

in  which  sewage  is  treated  with  a  precipitant  such 
as  lime,  or  other  chemicals. 

Chemical  precipitation  as  a  means  of  sewage 
treatment  was  widely  introduced  during  the 
period  from  1885  to  1895,  and  was  thought  to 
promise  a  complete  solution  of  all  sewage  dis- 
posal problems.  In  Great  Britain  several  of  the 
large  cities  adopted  this  method,  among  which 
were  London,  Birmingham  and  Glasgow;  in 
America  the  cities  of  Providence,  Worcester,  and 
some  smaller  places  constructed  such  plants.  At 
present  the  method  is  unpopular.  It  is  costly 
to  operate,  produces  great  quantities  of  sludge 
and  does  not  give  an  effluent  free  from  causing 
a  nuisance.  The  State  of  Massachusetts  has 
ordered  Worcester  to  discontinue  the  stream  pol- 
lution caused  by  such  a  plant,  and  the  method  has 
been  abandoned  both  here  and  abroad,  by  most 
of  the  cities  that  once  were  enthusiastic  about 
such  plants. 

Plain  sedimentation  without  the  use  of  chemi- 
cals, in  tanks  of  the  ordinary  type,  involves  the 
filling  of  a  tank  with  sewage,  which  is  then  al- 
lowed to  stand  long  enough  for  deposition  of  the 
heavier  solids.  Then  the  sewage  is  discharged 
and  the  settled  matters  removed,  usually  by  hand. 
The  settled  matters  are  very  foul  and  offensive 
and  require  special  treatment  and  disposal.  A 
more  advanced  design  of  these  tanks  is  provided 
with  a  bottom  consisting  of  one  or  more  inverted 

77 


Biological  {Treatment  of  Sewage 

pyramids  or  hoppers,  each  hopper  having  a 
sludge  pipe  outlet,  through  which  the  settled  mat- 
ters may  be  removed  by  gravity. 

This  form  of  tank  often  creates  bad  odors,  espe- 
cially if  the  settled  matters  are  not  removed  fre- 
quently. Such  tanks  also  cause  much  of  the 
suspended  matter  to  dissolve,  or  to  break  up  into 
colloidal  matter,  and  as  oxygen  exhaustion  usu- 
ally intervenes  in  this  operation,  and  a  vast  in- 
crease of  bacteria,  the  sewage  effluent  is  worse, 
and  more  foul  than  it  was  before  entering  the 
tank,  and  more  likely  to  cause  a  nuisance  near  the 
outlet  of  the  sewer. 

The  solution  of  suspended  matters  and  their 
apparent  disappearance  in  tanks  from  the  sew- 
age several  years  ago,  misled  many  engineers 
to  the  conclusion  that  a  complete  biological 
method  of  sewage  treatment  had  been  dis- 
covered, which  was  effected  by  anaerobic  bac- 
teria. Further  studies  resulted  in  the  so-called 
septic  tank.  Much  was  claimed  for  this  tank, 
but  it  actually  accomplished  very  little.  The 
tanks  at  Columbus,  Ohio,  and  at  Baltimore,  were 
among  the  largest  of  this  type.  The  latter  con- 
tinue in  service,  the  sludge  being  taken  from  them 
before  the  septic  process  is  complete,  and  carried 
to  completion  in  separate  digestion  tanks.  The 
septic  tank  generally  caused  bad  smells.  Sewage 
ran  through  it  continuously  with  a  detention  due 
to  the  size  of  the  tank,  varying  from  8  to  24 

79 


Sanitation  of  Cities 

hours.  Some  tanks  were  covered,  and  some 
opened  at  the  top;  a  heavy  scum  of  floating  mat- 
ter and  grease  covered  the  surface  of  the  sewage, 
and  helped  to  prevent  the  escape  of  foul  smells; 
but  much  of  the  hydrogen  sulphide  and  other 
gases  was  carried  out  of  the  tank  with  the 
effluent,  which  was  foul,  black  and  highly  putres- 
cible. 


80 


C     £    A    N 


LEGEND 


—  Scut   ~  Macs— 


!  U«»EAJTRMR,HU050N&B>Y  DIVISION 

I  JAMAICA  BxrOwuioN 
ItammflmM 


NEW  YORK  CITY,  N.  Y. 

Chart  showing  proposed  number  and  location  of  district  or  divi- 
sional sewage  treatment  plants  (indicated  by  black  symbols) 
suggested  by  the  Metropolitan  Sewerage  Commission 


81 


CHAPTER  VIII 

DIFFICULT  PROBLEMS  FOUND  IN 
TREATING  SEWAGE 

ONE  of  the  greatest  difficulties  connected  with 
sewage  treatment  is  the  disposal  of  sludge  from 
septic  tanks  and  settling  tanks,  as  the  sludge  from 
these  tanks  is  highly  putrescible.  This  has  led  to 
the  invention  of  two  forms  of  tanks,  each  of  which 
attempts  to  carry  the  septic  treatment  of  the 
sludge  to  such  a  point  that  when  discharged  it  will 
not  cause  a  nuisance. 

These  tanks  depend  upon  the  assumption  that 
when  the  so-called  septic  action  has  been  carried 
to  its  extreme,  the  unstable  organic  matters  which 
are  attacked  by  anaerobic  bacteria,  become  in- 
capable of  further  putrescence  and  dissolve,  or 
split  up;  part  going  into  solution,  part  into  inert 
matters,  and  part  remaining  as  organics,  that  do 
not  readily  putrefy,  which  are  deposited  with  the 
mineral  materials  present  on  the  bottom  of  the 
tank. 

The  greatest  problem  met  by  designers  of  tanks 
has  been  to  design  a  tank  in  which  the  reten- 

83 


<  .y 

§i 

§ 


Q   g 


00 

rt 


84 


^Difficult  problems  ifounb  in  treating  Sewage 

tion  of  these  putrefying  matters  would  not  cause 
them  to  mix  with  the  incoming  sewage,  and 
render  it  highly  "septic/'  or  putrescent,  as  it  left 
the  tank.  This  was  the  great  difficulty  with  the 
original  septic  tank. 

The  first  two-stage,  or  two-story,  tank  was  in- 
vented in  England  about  fifteen  years  ago  and 
was  known  as  the  Travis  tank.  It  is  provided 
with  two  upper,  or  flowing-through  chambers,  the 
bottoms  of  which  are  inclined  at  an  angle  of  about 
45  degrees  and  are  provided  at  the  lowest  point 
with  ports,  or  openings,  into  the  lower  chamber 
which  was  placed  between  the  two  upper  cham- 
bers, through  which  the  settlings  and  sludge  pass 
by  gravity.  The  lower,  or  digesting,  chamber  has 
its  bottom,  which  is  the  deepest  part  of  the  tank, 
formed  in  one  or  more  hoppers,  or  inverted  pyra- 
mids, provided  with  sludge  outlet  pipes.  The 
upper  part  of  this  chamber  is  at  the  same  eleva- 
tion as  the  upper  part  of  the  flowing-through 
chambers,  and  a  portion  of  the  sewage  is  per- 
mitted to  pass  through  it.  The  flowing-through 
chambers  have  a  network  of  slats  formed  into 
trellises  which  are  placed  across  the  direction  of 
the  flow,  the  purpose  of  which  is  to  act  as  a 
remover  of  colloids  by  "adsorption/'  it  being 
claimed  that  fine  particles  of  organic  matter  in 
a  colloidal  state  tend  to  adhere  to  surfaces  where 
they  are  readily  attacked  and  liquefied  by  bac- 
teria. 

85 


Sanitation  of  Cities 

But  few  plants  with  tanks  of  this  type  have  been 
built.  The  effluent  was  little  if  any  better  than 
from  a  septic  tank.  The  sludge  was  not  suf- 


ESSEN,  GERMANY 
Imhoff  tank  sewage  treatment  plant 

ficiently  digested  to  dry  on  a  bed  without  causing 
odors.  At  Norwich,  England,  using  this  system 
it  was  necessary  to  dispose  of  the  sludge  in 
trenches. 

The  Imhoff  tank  is  a  more  successful  effort 
to  solve  this  very  difficult  problem.  Invented 
at  Essen  in  Germany,  it  is  a  further  development 
of  the  Travis  principle.  It  discards  the  "col- 
loiders,"  and  provides  two  chambers,  an  upper 
or  flowing-through  chamber  for  the  sewage,  in- 
tended for  plain  sedimentation,  and  a  lower  or 
digestion  chamber,  for  the  settling  matter  or 
sludge.  The  upper  chamber  is  designed  with 
sharply  sloping  bottom  surfaces,  provided  with 

86 


Difficult  problems  tfounb  in  treating  Sewage 

slots  at  the  lowest  point,  through  which  the  set- 
tlings enter  the  lower,  or  digesting  chamber:  a 
baffle  or  fender  is  arranged  under  the  slots  to  pre- 


BALTIMORE,  MARYLAND 
Imhoff  tank  sewage  treatment  plant 

vent  the  gases  arising  from  the  digesting  matters 
from  entering  the  upper  chamber.  The  lower 
chamber  is  provided  with  vents  or  chimneys 
which  reach  the  surface  to  permit  the  escape  of 
gases  into  the  air. 

Many  tanks  of  this  form  have  been  built, 
especially  in  Germany,  and  when  properly  de- 
signed and  operated  with  a  very  short  detention 
period  this  has  proved  to  be  the  best  type  of  tank. 

The  septic  process  is  essentially  a  fermentation 
and  rotting  out  process.  It  is  an  attempt  to  let 
nature  take  her  course,  in  carrying  out  the  various 
changes  that  are  required,  for  the  partial  or  com- 

87 


Sanitation  of  Cities 

plete  decay  of  organic  solids;  but  confining  the 
nuisance,  and  odorous  process,  within  the  limit 
of  a  tank.  It  now  is  well  understood  that  this 
process  requires  a  long  time  to  accomplish  much 
of  value  in  the  reduction  of  organic  solids;  and 
that  the  danger  of  a  nuisance  is  present,  in  the 
tanks  so  far  designed. 


LONG  BEACH,  CALIFORNIA 

R-W  screen   sewage   treatment 

plant   adjacent   to   bathing 

beach   shown   in   small 

insert 


88 


CHAPTER  IX 

THE  MECHANICAL  TREATMENT 
OF  SEWAGE 

THE  natural  agencies  employed  under  operating 
conditions  sometimes  escape  from  the  control 
under  which  the  septic  type  of  plant  attempts  to 
place  them,  and  cause  odors  and  a  more  or  less 
active  nuisance.  Since  the  first  tank  was  used, 
objections  have  been  made  on  the  part  of  the 
public,  and  sanitary  engineers  have  sought  for 
other  methods  of  freeing  sewage  from  matters  in 
suspension.  It  was  noted  soon  after  tanks  began 
to  be  used  that  they  did  not  give  a  very  high 
removal  of  total  solids  from  the  sewage,  and  that 
much  suspended  matter  passed  from  suspension 
into  solution,  making  the  liquid  part  more  foul 
than  before,  especially  if  subjected  to  long 
periods  of  detention. 

An  obvious  principle  of  sewage  treatment  is, 
that  the  quicker  the  polluting  organic  solid  mat- 
ters are  removed  from  the  liquid  part  the  better, 
as  this  prevents  solution  of  the  solids;  it  also 

89 


Gbe  flDecbanical  treatment  of  Sewage 

keeps  the  sewage  from  becoming  septic,  and  pre- 
vents the  vast  increase  of  bacteria  that  a  long 
period  of  treatment  invites. 

As  sedimentation  was  at  best  a  slow  pro- 
cess, and  could  seldom  escape  causing  septic 
conditions,  it  was  asked,  "Can  we  not  find  a 
mechanical  method  of  treatment  which  will  re- 
move the  suspended  solids  at  once?"  On  this 
problem  engineers  and  scientists  have  been  en- 
gaged many  years.  Much  of  this  work  was  done 
in  Germany  where,  as  in  America,  with  large 
rivers,  conditions  were  favorable  to  the  discharge 
of  fresh  liquid  sewage  if  freed  from  suspended 
matters  above  a  certain  size,  without  further 
treatment.  In  England  the  streams  as  a  rule  are 
so  very  small  that  the  mere  removal  of  fresh 
suspended  solids  was  not  usually  sufficient,  and 
filtration  was  required  in  any  case;  and  having 
started  by  using  tanks  before  filtration,  the  con- 
servative English  engineer  has  been  slow  to  take 
advantage  of  progress  made  elsewhere. 

Much  has  been  published  about  the  success  of 
the  mechanical  treatment  of  sewage  in  Germany. 
For  the  present  purpose  it  need  only  be  stated  that 
the  quick  removal  effected  by  fine  screens  of  the 
suspended  matters  above  a  certain  predetermined 
size — to  be  decided  upon  to  meet  the  local  needs — 
has  been  very  successful. 

The  evidence  of  this  success  has  appealed  so 
strongly  to  American  engineers  familiar  with  Ger- 

91 


flDecbanical  treatment  of  Sewage 

man  fine  screen  plants  that  the  introduction  of 
fine  screens  for  treating  sewage  in  the  United 
States  has  made  rapid  progress,  and  is  giving  gen- 
eral satisfaction. 

There  are  a  great  many  such  plants  abroad, 
some  of  notable  interest;  of  which  Dresden  may 
be  mentioned  as  a  type  and  as  the  largest  instal- 
lation, where  the  sewage  of  an  entire  city,  having 
a  population  of  about  600,000,  is  fine  screened  as 
its  only  preparation  for  discharge  into  the  Elbe 
River,  a  small  stream  at  this  place,  and  more 
than  400  miles  from  the  sea. 

A  principle  followed  in  the  design  of  sewage 
treatment  plants  in  Germany  has  been,  first,  to 
improve  the  river  that  is  to  receive  the  effluent, 
so  as  to  improve  its  capacity  to  afford  dilution, 
and  at  the  same  time  render  it  better  able  to  carry 
river  transportation.  Thus  a  commercial  water- 
way of  great  economic  value  can  be  created,  with 
part  of  the  funds,  and  the  cost  of  sewage  treat- 
ment greatly  reduced.  To  prevent  nuisance  in 
the  unimproved  stream  would  have  required  a 
much  higher  grade  of  treatment,  and  greater  in- 
vestment of  money  in  plant,  as  well  as  more 
costly  operation. 

Having  regulated  and  dredged  the  river,  it  has 
usually  been  found  that  the  needed  expenditure 
for  sewage  treatment  has  been  reduced  more  than 
half,  and  a  prosperity  producing  improvement 
obtained,  for  money  that  would  otherwise  have 

93 


94 


flDecbanical  treatment  of  Sewage 

been  locked  up  in   a  costly  sewage  treatment 
plant. 

It  may  confidently  be  stated  that  in  America 
with  its  large  rivers,  more  than  half  of  the  money 
used  in  sewage  disposal  plants,  and  expensive 
main  drainage  systems,  would  far  better  have 
been  expended  on  the  improvement  of  the  rivers; 
with  the  two  objects  in  view  of  making  them 
valuable  commercial  assets,  and  of  reducing  the 
need  of  sewage  treatment  expense  to  a  minimum. 
Dredging  commercial  waterways  and  deep  chan- 
nels, not  only  provides  for  water-borne  freight, 
but  also  greatly  increases  the  quantity  of  water 
present  available  for  sewage  dilution,  and  pro- 
vides favorable  conditions  for  the  mechanical 
treatment  of  sewage.  The  danger  from  floods  is 
also  greatly  reduced,  and  the  natural  drainage  of 
extensive  tracts  of  country  much  improved; 
swamps  and  marsh  lands  are  dried,  directly  pre- 
venting malarious  conditions,  and  destroying  the 
breeding  places  of  mosquitos.  The  commercial 
and  sanitary  conditions  are  all  benefited  by  such 
use  of  money — and  the  saving  in  cost  of  sewage 
treatment  is  large.  Money  used  in  waterway  im- 
provements gives  immense  returns  on  the  invest- 
ment, while  that  used  on  sewage  treatment  plants 
—notwithstanding  their  sanitary  importance — is 
locked  up  forever. 


95 


DRESDEN,  SAXONY 

Interior  view  of  the  screen  house,  showing  general  arrangement  of 

the  Riensch-Wurl  screens  (each  twenty-six  feet  three  inches 

diameter),  screen  bridges,  motors  and  driving  mechanism, 

with  elevators  for  screenings,  effluent  discharge 

channel  at  left 


CHAPTER  X 
THE  PURIFICATION  OF  SEWAGE 

FROM  the  foregoing  considerations  we  now  turn 
to  the  need  of  a  more  complete  treatment  of  sew- 
age than  the  removal  of  suspended  matter  will 
give.  Such  treatment  may  be  required  if  the  efflu- 


BALTIMORE,  MARYLAND 

Trickling  filter  bed,  the  largest  plant  of  this  type  in  the  United  States 

ent  is  to  be  discharged  into  a  stream  so  small  that 
the  diluting  water  will  not  provide  biological  puri- 
fication without  putrescence.  The  means  of  giv- 

97 


•p 

OJ 

Jo 


> 


3I 

z  "L 

LJU    ^ 

CD    M- 


98 


purification  of  Sewage 

ing  this  higher  grade  of  purity  to  the  sewage  is 
strictly  biological,  and  the  designs  used  in  such 
plants  have  for  their  object  the  cultivation  of 


BALTIMORE,  MARYLAND 

Sewage  treatment  plant,  showing  two  cylindrical  screens  for  treating  the 
sewage  after  passing  through  tanks  prior  to  entering  filter  beds 

aerobic  bacteria  under  control,  and  in  the  presence 
of  a  plentiful  supply  of  oxygen. 

The  standard  methods  now  used  are  all  sec- 
ondary forms  of  treatment;  that  is,  the  sewage  has 
already  passed  through  a  stage  of  preparation  by 
which  suspended  solids  have  been  removed  to  a 
greater  or  lesser  extent.  Examples  are  shown  in 
the  accompanying  illustrations  of  the  various 
forms  of  plants  used  for  the  purpose. 

It  would  be  useless  to  attempt  a  detailed  com- 
parison of  the  methods  of  secondary  or  oxidation 
treatment.  The  installation  of  such  plants  is  sel- 
dom really  necessary,  and  much  public  money  has 
been  uselessly  expended  in  the  futile  attempt  to 

99 


IOO 


purification  of  Sewage 

make  drinking  water  out  of  sewage.  The  real  and 
usually  the  only  requirement  is  to  prevent  a 
nuisance  in  a  stream  or  waterway  the  use  of  which 
is  unavoidable  for  sewage  discharge. 

In  Chicago  a  few  years  ago,  a  board  of  consult- 
ing engineers  considered  various  plans  for  the 
sewage  disposal  of  that  city.    One  of  these  plans 
consisted  of  primary  and  secondary  treatment  by 
means  of  tanks,  followed  by  sprinkling  filters  of     tf 
immense  size  and  capacity;  the  other  was  for  a     E 
canal  connecting  the  waters  of  Lake  Michigan^  u 
with  the  Illinois  River,  thereby  creating  a  great§  5 
commercial  waterway,  into  which  the  entire  sew-^  w 
age  of  the  city  could  be  discharged,  and  com-5  =J  j 
pletely  treated  by  the  mere  dilution  thereof,  with£j  o  o 
the  waters  of  the  canal. 


to   h 
E   z 

U    U 

>     2 

1 

111 

O 


CITY  OF  CHRISTIANIA,  NORWAY 

View  of  waterfront  and  Riensch-Wurl  treatment  plant  (indicated  by 

arrow).    Note  class  of  residential  buildings  in  immediate  vicinity 

of  the  plant  and  pleasure  craft  in  the  harbor  into  which 

the  screened  effluent  is  directly  discharged 

The  result  to  be  obtained  by  the  first  method 
at  best  was  uncertain,  and  the  period  of  time  dur- 
ing which  it  would  be  sufficient  was  doubtful. 

101 


102 


purification  of  Sewage 

The  success  of  such  a  plant  depended  principally 
on  perfect  care  and  first-class  ability  being  ap- 
plied to  its  operation  and  maintenance.  At  best, 


VIEW  OF  CITY  OF  CHRISTIANIA,  NORWAY 
Showing  location  of  screening  plant,  indicated  by  arrow 

the  very  large  cost  would  give  nothing  of  com- 
mercial value.  Its  condition  would  rapidly  de- 
preciate in  service,  and  in  a  few  years  call  for  ex- 
tensive repairs,  and  finally  for  reconstruction.  It 
would  require  many  acres  of  valuable  land  which 
besides  first  cost,  would  be  removed  permanently 
from  industrial  or  home  development;  and  large 
surrounding  areas  would  probably  be  rendered 
undesirable  by  the  presence  of  the  plant,  which 
would  cause  local  nuisance  and  depreciate  prop- 
erty values. 

The  canal  avoided  these  objections.  The  water 
available  for  dilution  afforded  a  satisfactory 
treatment,  and  insured  the  inoffensive  oxidation 
of  sewage  pollution  within  a  few  miles  of  the  en- 
trance of  the  sewage.  No  valuable  land  was  to 
be  taken  from  its  natural  development  and  tax- 
able value;  and  taxable  values  would  be  in- 

103 


Gbe  Sanitation  of  Cities 

creased,  instead  of  diminished,  by  the  presence 
of  the  canal,  as  its  commercial  possibilities  be- 
came evident. 

The  commission  wisely  decided  upon  the  canal, 
which  is  now  completed,  and  gives  Chicago  a  com- 
manding commercial  situation,  since  through  it 
can  come  to  its  gates  the  commerce  of  the  Missis- 
sippi and  its  tributaries  which,  when  fully  devel- 
oped as  they  are  almost  certain  to  be,  will  lead 
a  flood  of  gold  into  her  commercial  channels. 


104 


CHAPTER  XI 

DEVELOPMENT  OF 

COMMERCIAL  WATERWAYS  AS  A 

SANITARY  MEASURE 

THE  development  of  the  internal  commerce  of 
the  United  States  is  one  of  the  most  important 
interests  of  our  nation.  With  the  great  increase 
in  cost  of  railroad  operation,  resulting  from  a 
diminishing  coal  supply  and  lack  of  labor,  the 
return  of  river  and  canal  transportation  for 
freight  is  to  be  expected.  Our  country  is  far  be- 
hind the  old  world  in  this  respect;  there,  a  large 
portion  of  freight,  especially  in  heavy  bulk,  is 
carried  by  steamboats  and  barges,  and  the  regu- 
lation of  rivers  and  waterways  and  canal  devel- 
opments have  been  brought  to  a  high  point  of 
efficiency.  We  are  just  about  making  a  start  in 
this  line,  and  the  prosperity  of  many  cities  is 
deeply  concerned  in  the  progress  of  this  means  of 
transportation.  Cities  served  by  railroads  only 
may  within  a  few  years  find  themselves  outclassed 
by  more  fortunate  rivals  possessing  river  and 
canal  facilities. 

105 


io6 


Waterways  as  a  Sanitary  Measure 

The  Great  Lakes  form  a  chain  of  inland  seas 
which  are  paralleled  by  many  of  the  great  rivers 
at  approachable  distances  for  connection  by 
canals.  The  development  and  regulation  of 
these  rivers,  with  canals  passing  from  them  to 
the  lakes,  will  afford  the  most  splendid  internal 
commercial  waterways  in  the  world,  and  one  of 
the  greatest  projects  ever  proposed  by  the  civil 
engineering  profession. 

Of  such  canals,  the  New  York  Barge  Canal  is 
the  most  important  that  has  been  realized  in 
completed  form.  That  it  is  to  be  only  the  first 
among  others  as  important  is  confidently  antici- 
pated. Now  that  New  York  has  opened  this  im- 
mense opportunity  for  reducing  the  cost  of  traf- 
fic, others  will  soon  follow. 

The  sanitation  of  cities  situated  on  rivers  that 
can  be  improved  to  afford  much  larger  volumes 
of  water  than  at  present,  and  on  canals  compar- 
able in  size  to  the  Chicago  drainage  canal  can, 
by  developing  their  waterways  and  making  exist- 
ing channels  deeper  and  wider,  save  much  of  the 
cost  required  for  sewage  treatment  plants.  The 
money  saved  by  thus  avoiding  the  necessity  for 
constructing  vast  sprinkling  filter  beds,  etc.,  can 
be  applied  to  improvements  of  a  more  desirable 
and  profitable  kind. 

The  New  York  State  Barge  Canal,  beginning 
at  Buffalo,  will  carry  an  ever  increasing  stream  of 
commerce  to  New  York  and  Brooklyn,  and  this 

107 


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Waterway  as  a  Sanitary  flDeasure 

will  have  an  important  effect  on  many  local  sani- 
tary problems.  Jamaica  Bay,  a  large  but  shal- 
low body  of  water  within  the  area  of  the  city 
of  New  York,  and  adjoining  the  harbor,  was  be- 
coming polluted  with  sewage,  and  was  negligible 
in  commercial  value  because  of  the  high  cost  of 
dredging,  until  the  prospect  of  the  traffic  to  be 
anticipated  from  the  new  barge  canal  made  its 
value  apparent,  and  plans  were  prepared  for  its 
extensive  improvement.  It  was  then  found  that 
with  the  newly  dredged  channels,  required  for 
commerce,  the  sanitary  problem  had  been  much 
simplified;  that  biological  sewage  treatment 
plants  consisting  of  sprinkling  filters  for  the 
treatment  of  sewage  entering  the  new  channels, 
would  not  be  necessary;  and  that  money  thus 
saved  might  be  used  on  other  improvements. 

There  are  doubtless  many  other  places  where 
dredging  adequate  channels  in  a  stream  or  harbor 
for  the  benefit  of  commerce  would  also  solve  the 
problem  of  sewage  treatment  to  such  an  extent 
that  the  cost  of  treatment  plants  would  be 
reduced  more  than  half,  and  risks  of  nuisance 
entirely  disappear.  Such  problems  invite  the 
serious  study  of  municipal  officials  before  they 
authorize  the  expenditure  of  large  sums  of  money 
on  disposal  plants  that  would  become  needless, 
should  the  river  or  harbor  be  properly  dredged 
for  shipping. 


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I  10 


CHAPTER  XII 
HIGH  PRESSURE  FIRE  SERVICE 

THE  health  and  prosperity  of  the  community 
depend  upon  pure  water,,  sanitary  conditions, 
successful  industry,  and  facilities  for  ready  trans- 
portation of  freight  and  persons.  The  public 
does  not  fully  or  properly  comprehend  the  ben- 
efits to  be  derived  from  a  general  and  thorough 
study  of  municipal  problems  in  the  supply  of 
pure  water  and  the  treatment  and  disposal  of 
sewage,  rubbish,  and  garbage,  as  parts  of  a  com- 
mon municipal  development. 

The  reasonable  procedure  to  follow  would  be 
to  have  trade  wastes  treated  prior  to  discharge 
into  the  municipal  sewers,  so  that  such  wastes 
would  be  at  least  in  a  condition  comparable 
with  the  domestic  sewage  of  the  city.  Moreover, 
the  value  of  by-products  to  be  derived  from  this 
treatment  of  trade  wastes  should  be  of  special 
interest  to  the  manufacturer. 

The  problems  of  city  sanitation  include  and 
merge  into  the  more  general  problems  of  the  pub- 
lic welfare.  The  agencies  of  municipal  govern- 

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ment  are  all  provided  for  that  one  end  and 
purpose — city  sanitation  and  municipal  welfare 
go  hand  in  hand.  The  administration  with  its 
executive,  police,  health,  street-cleaning,  engi- 
neering, and  fire  protection  departments,  etc.,  all 
should  be  considered  in  connection  with  the  pub- 
lic welfare  and  city  sanitation.  It  is  not  possible 
in  such  a  brief  survey  as  this  study  intends  to  go 
further  into  detail  as  to  the  influence  of  all  these 
and  other  municipal  departments  on  the  sanita- 
tion of  cities;  but  the  effect  of  each  is  obvious— 
a  full  accounting  of  the  progress  made  in  the  de- 
velopment of  all  of  the  various  agencies  of  city 
welfare  would  be  most  interesting.  For  illustra- 
tion on  this  point  we  may  take  the  single  feature 
of  fire  protection — a  most  important  and  inter- 
esting subject  in  itself — affording  a  rather  strik- 
ing picture  of  municipal  progress.  Not  many 
years  ago  our  fathers  were  satisfied  with  bucket 
brigade  fire  protection,  and  each  solid  citizen  of 
the  last  century  had  his  half-dozen  leathern  buck- 
ets, marked  with  his  initials  and  the  words  'Tor 
fire  only/'  hanging  in  his  hall  at  a  convenient 
place,  ready  for  the  emergency  when  the  fire  bell 
should  call  out  all  of  the  volunteer  fire  laddies. 
Next  came  the  well-known  fire  engine,  still  with 
us;  and  in  the  fullness  of  time  came  the  high  pres- 
sure service,  with  its  powerful  pumps,  typifying 
modern  progress. 

The  practice  of  protecting  the  congested  busi- 

"3 


1bigb  pressure  fire  Service 

ness  districts  of  our  greater  cities  by  means  of 
high  pressure  fire  service  is  now  so  well  established 
that  we  can  scarcely  realize  the  feelings  of  busi- 
ness men  in  the  past,  before  the  adoption  of  this 
system,  who,  on  leaving  their  offices  and  ware- 
houses at  night,  were  always  haunted  by  the  dan- 
ger of  destructive  conflagration  before  morning. 
The  experiences  of  Chicago,  Boston,  and  Balti- 
more are  still  fresh  in  the  public  memory;  but  with 
the  new  high  pressure  protection  the  danger  has 
largely  vanished.  A  few  pictures  of  some  of  these 
stations  are  included  as  an  indispensable  feature 
of  this  study.  Greater  New  York  was  the  first 
city  to  install  such  a  fire  protection  service.  The 
first  high  pressure  stations  were  constructed  in  the 
Borough  of  Brooklyn,  followed  soon  by  stations 
in  the  Boroughs  of  Manhattan  and  of  Richmond. 
Not  only  cities  of  the  first  class,  such  as  New 
York,  Philadelphia,  San  Francisco,  etc.,  have  in- 
stalled high  pressure  fire  service,  but  many 
smaller  and  no  less  progressive  cities — such  as 
Miami,  Florida,  for  instance — have  also  estab- 
lished this  protective  method  of  fire  protection; 
and  almost  every  American  city  not  yet  so  pro- 
tected now  has  the  project  under  advisement, 
and  it  is  generally  admitted  by  all  authorities 
that  no  subject  can  be  of  more  urgent  importance. 


115 


n6 


CHAPTER  XIII 
CONCLUDING  REMARKS 

CONSIDERING  the  vastness  of  the  subject,  we 
have  presented  a  very  brief  review  of  the  Sani- 
tation of  Cities.  With  our  rapidly  increasing 
population,  and  the  almost  magical  growth  of 
cities;  with  problems  of  housing,  providing 
markets,  means  of  industry,  and  of  recreation, 
etc.,  into  all  of  which  sanitary  questions  enter, 
the  immensity  of  the  sanitation  of  cities  prob- 
lems is  apparent.  Of  necessity,  we  have  been 
forced  to  limit  the  various  questions  discussed  to 
broad  principles. 

A  thought  that  we  wish  to  convey  in  con- 
clusion is  the  unity  of  municipal  problems,  and 
particularly  the  problems  relating  to  Sanitation. 
It  may  be  said  that  these  problems  are  really 
one,  which  might  be  generalized  as  the  "Human 
Problem." 

Wastes  of  all  kinds  are  the  result  of  human 
life;  whether  derived  from  the  home  or  the 
factory,  they  must  be  disposed  of.  Pure  water 
must  be  obtained  and  supplied  in  an  unfailing 

117 


18 


Conclubing  IRemarfcs 

stream,  regardless  of  cost,  but  funds  must  be  ex- 
pended with  a  wise  economy.  To  these  matters 
we  have  given  our  principal  attention  in  this 
study. 

It  is  evident  that  we  have  been  discussing  but 
one  problem  of  many  parts,  and  that  it  is  of  such 
extent  that  even  if  presented  in  many  more  pages 
than  we  have  used,  the  subject  would  be  far  from 
exhausted.  The  most  we  can  hope  for  is  that  in 
a  brief  space  we  have  given  the  reader  a  picture  of 
some  of  the  larger  problems  involved,  at  least,  with 
well  defined  outlines  of  the  Sanitation  of  Cities. 


119 


Designed  and  Illustrated  by 
FRANKLIN  V.  SIKES,  Inc.,  Neu;  York 

Printed  by 

THE  DE  VINNE  PRESS,  Neu;  York 


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JAN  27  1937 

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